Assembled media pipelines with at least one media pipeline, which is heatable, and at least partially heatable pipeline connectors are known in the prior art. In vehicles in particular, media pipelines for conveying at least fluid media are provided. At low temperatures, the media pipelines threaten to freeze, for which reason, heating is provided. Pipeline connectors are used for connecting at least two media pipelines or for the connector connection of a media pipeline to a desired unit. Often such media as tend to freeze even at still quite high environmental temperatures, owing to a relatively high freezing point, are conveyed through the media pipelines, as a result of which the functionality, for example, of a vehicle may be impaired or even disturbed considerably. This is particularly apparent in the case of water pipelines for windscreen-washing systems, just as in the case of media pipelines, by means of which aqueous carbamide solution is transported as a medium, which is used as NOx reaction additive for diesel engines with so-called SCR catalytic converters.
The two connection ends of the assembled heatable media pipeline are usually formed by two pipeline connectors attached at the end of the media pipeline. The heating elements are used for heating the media pipeline and/or the connection ends or pipeline connectors. For this purpose, the same may be arranged internally and/or externally on the media pipeline and the connection ends or pipeline connectors. The heating elements can be wired electrically in series and connected to a common current or voltage source.
It is further known from WO 2010/063629 to operate the heating elements electrically parallel and to supply each heating element separately with an operating current controlled or regulated for adjusting the heating output thereof. Here, each heating element is separately supplied with an own operating voltage, wherein each operating voltage is generated from a supply voltage by means of a pulse-width modulation control clocked with a certain pulse duty cycle for regulating the heating output. The resulting operating current of each heating element results from the effective value of the clocked, pulsed operating voltage and an in each case instantaneous, temperature-dependent resistance of the heating element.
Furthermore known from WO 2008/131993 A1 is the provision of an electrical series connection, as well as a parallel connection of the heating wires of the assembled media pipeline. Furthermore, this published document of the prior art discloses that the heating wire of one of the pipeline connectors is in each case electrically series connected to one of the wire windings of the pipeline and the connection ends of the two series connections at one of the two pipeline connectors in each case are guided outwards for connection of a voltage supply and/or for further connection. The heating conductor can be arranged along the pipeline in such a manner that the electrical resistance thereof is different in certain sections, so that different heating outputs are generated in certain sections.
In these assembled media pipelines of the prior art, individual heating elements or heating wires can therefore be connected to one another in series and/or parallel in each case. Furthermore, it is possible according to WO 2010/063629 A2 to supply the individual heating elements with electrical energy separately from one another and thereby to adjust the respectively required heating output. In the application of such heatable media pipelines, the problem often results, that a different heat requirement exists at the two connection ends of the media pipeline, particularly the two pipeline connectors.